Coupled Natural-Human Systems and Emerging Infectious Diseases: Anthropogenic

environmental change and avian influenza in Vietnam

Jefferson Fox

East-West Center

Project Collaborators East-West Center

Jeff Fox, Nancy Lewis, Sumeet Saksena, Melissa Finucane

University of HawaiiJim Spencer, Dept. Urban and Regional PlanningBruce Wilcox, Dept. Public Health, IGERT ProgramIan Pagano, Cancer Research Center

Hanoi University of AgricultureTran Duc Vien, RectorNguyen Thanh Lam, Dept. Environmental TechnologyTrinh Dinh Thau, Faculty of Veterinary MedicineMichael DeGregario

Swiss National Center of Competence in ResearchMichael Epprecht

Introduction Unraveling mechanisms that underlie new

and reemerging infectious diseases (EID) requires exploring complex interactions within and among coupled natural and human (CNH) systems and poses one of the most difficult scientific problems facing society today (Wilcox and Colwell 2005).

Factors Involved in Disease Emergence

Question: Is the risk of AI is related to anthropogenic environmental changes?

Smith (1990) proposed an environmental risk transition where the environmental factors leading to ill health were categorized as traditional or modern.

Traditional diseases are problems at the household level (e.g., water, sanitation, food availability and quality, ventilation and indoor air pollution).

Modern diseases tend to operate at the community level (i.e., urban air quality, occupational hazards, toxic chemicals and motorization).

Project Objectives

1. To test the Wilcox-Colwell hypothesis that anthropogenic transformations such as urbanization, agricultural change, and natural habitat alteration affect the emergence and reemergence of infectious diseases. We will test this model in Vietnam using data collected at national, commune, and household scales.

2. To examine the influence of socio-ecological and socio-psychological variables on individuals' perceptions of and responses to the risk of HPAI in traditional, transitional, and modern communes.

Objectives (continued)3. To integrate this study with education programs at

the University of Hawaii including the Integrative Graduate Education and Research Traineeship (IGERT) program that focuses on “Integrative Training in Ecology, Conservation and Pathogen Biology”.

4. To establish collaboration among scientists from multiple disciplines and among U.S. institutions and partners from Vietnam and other countries in the Asia Pacific region. To develop activities that ensure research opportunities and mentoring for large numbers of students.

Emergence of AI in Vietnam

First reported at the end of 2003

Three major epidemic waves

45 million birds culled between Dec 2003 and August 2005

As of 2008, 106 confirmed human cases, 52 deaths

Massive, repeated vaccination campaigns

Anthropogenic environmental transformations alter host-pathogen relationships

Spillover into new hosts Rapid pathogen adaptation More frequent novel variants Range expansion What are the mechanisms

underlying EIDs? Need to examine CNHS

interactions

Chickens and water birds prominent in livestock sector

Integrated agriculture-aquaculture system

Poultry traded at live bird markets, involving mixing and frequent movement of live animals

Opportunities for interaction with both infected domestic and wild water birds

Phase I: Kuznet’s Curves and Transition Index

Vietnam’s 1999 Census of Population and Housing provides counts of households by housing construction materials (traditional/temporary or modern), water supply (stream, rain, well, piped), and sanitation infrastructure (none, pit, composting, flush).

Converted each of these 4-category, ranked urbanization measures into four distinct measures of settlement “coherence”.

For each coherence measure, greater mixing (i.e. incoherence) of the four categories was set to center on a value of zero, with more “traditional” settlements dominated by the least sophisticated (e.g. no toilet) category valued at (-1), and the most “modern” settlements dominated by the most sophisticated (e.g. running water) valued at (+1).

Transition Index (TI) This suggests that for the

urbanization measure, at least those measures centered on water supply and sanitation, the basic function may be a Kuznets curve.

We intend to conduct similar exercises for agricultural change and habitat alteration.

We will develop transition indices for agricultural change and habitat alteration, plot them against the probability of HPAI outbreak, and choose the curve that best fits the data.

Phase II: Commune and Households

Once we have explored the relationship between HPAI and urbanization, agricultural change, and habitat alteration at the national level, we will examine whether this relationship exists at commune and household scales using focus groups, interviews, and a structured household survey.